Work-table height adjusting means for blind-stitch sewing machines



April 8, 1958 F. PARRY WORK-TABLE HEIGHT ADJUSTING MEANS FOR BLIND-STITCH SEWING MACHINES 2 Sheets-Sheet 1 Filed Oct. 19, 1954 INVENTOR. Frank Parry ATTORNEY WITNESS April 8, 1958 F PARRY 2,829,614 WORK-TABLE HEIGHT ADJUSTING MEANS FOR BLIND-STITCH SEWING MACHINES Filed Oct. 19, 1954 2 Sheets-Sheet 2 4V l 1 g g :2; Q 9' LL.

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. s3, WITNESS 9 BY Frclnk Parry ATTORNEY United States Patent WGRK-TABLE HEIGHT ADJUSTING MEANS FOR BLIND-STITCH SEWING MACHINES Frank Parry, Trumbull, Conn., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application October 19, 1954, Serial No. 463,240

2 Claims. (Cl. 11-2--260) The present invention relates to blind-stitch sewing machines and has for a primary object to provide an improved work-table height adjusting means for blind-stitch sewing machines. Specifically, it is anobject of this invention to provide such a work-table height ad usting means of simplified construction and, therefore, economi' cal, and yet durable, capable of accurate adjustment, dependable and efficient in operation.

Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which:

Fig. 1 is a top plan view of a machine constructed in accordance with the present invention, the bed coverplate being removed and certain of the parts being in section to illustrate the details of the machine.

Fig. 2 is a vertical sectional view taken substantially on the line 22 of Fig. l longitudinally of the base of the machine and through the standard and the worktable, with some parts broken away.

Fig. 3 is a fragmentary detail sectional view taken substantially on the line 33 of Fig. 2.

Fig. 4 is a detail perspective of the work-table height adjusting element.

The present invention is illustrated in the drawings as embodied in a single-thread chain-stitch blind-stitch sewing machine of the type as disclosed, for example, in the U. S. patent of Parry, No. 2,678,619. The machine is herein illustrated and described only insofar as is necessary to obtain a full understanding of the present invention and it is to be understood that the various other details of the machine may be of any suitable construction.

The illustrated machine comprises a frame having a base 1 and a standard 2 rising from the right rear corner thereof and carrying the usual laterally extending horizontal arm 3 and forwardly extending frame-arm 4. The arm 4, in turn, carries the stitch-forming mechanism including the arcuately moving curved needle 5 and looper 6, and the four-motion feed-dog 8 and resser-plate 9. In the usual manner there is provided a work-table 10 which includes at its free end a tubular portion 11 that underlies the free end of the arm 4. The work-table 10 is pivotally mounted on the base 1 by means of trunnions 12 which extend inwardly from depending walls 13 of the work-table 10 and are pivotally received within appropriate bores in upstanding ears 14 of the bracket 15 that is fastened to the base 1 by bolts 16. The worktable is biased in the usual manner in the direction in which the tubular portion 11 is urged upwardly toward the presser-plate 9. The means for biasing the workta'ble comprises a spring 17 anchored at one end to the rear wall of the base 1 by an adjustable bolt 18 and secured at the other end to the depending apron 19 of "ice the work-table by an anchor-pin 20 threaded into the apron 19. The pivotal movement of the work-table under the action of the spring 17 is limited by an adjustable stop-screw 21 which is threaded through the apron 19 and contacts an adjustable abutment means comprising a cam surface 22 of an axial displacement cam 23. The cam 23 comprises a segment of a disc having the cam surface 22 formed upon the face thereof and .it is mounted upon the end of a work-table height adjusting shaft 24 which is arranged longitudinally in the bed 1 and journaled in bearings 25.

The spring 17 will act to pivot the work-table 10 about the trunnions 12 in a counterclockwise direction as seen in Fig. 2, and thus urges the tubular portion 11 thereof upwardly into working relationship with the stationary presser-plate 9, the action of the spring 17 being limited by contact of the screw 21 with the cam surface 22 of the cam 23 in the usual manner, the work-table 10 when in stop or normal elevated position is spaced from the presser-plate 9 and it carries resiliently-biased vertically yieldable work-clamping members 26 which urge the Work into engagement with the resser-plate. The height of the work-table 10 or amount of spacing of the same relative to the presser-plate 9 is set in accordance with the thickness of the goods being sewed in order to regulate the depth of penetration of the Work by the curved needle in the formation of blind stitches. It will, of course, be apparent that in the illustrated mechanism an angular adjustment or turning of the shaft 24 and, thus, of the cam 23 will effect an adjustment of the normal elevated position of the work-table 10.

The means for turning the shaft 24 and thus the cam 23 comprises a slide-rod 27 arranged vertically in the standard 2 for vertical sliding movement in a guide lug 28 integral with the standard 2. The slide-rod 27 is held against rotation by means of a pin 29 threaded through the lug 28 and into a longitudinal slot 30 in the periphery of the rod. At its lower end, the slide-rod 27 is enlarged and has formed therein a socket 31 that receives the ballshaped free end 32 of a crank-arm 33 threaded into a suitable bore in the shaft 24 and extending laterally therefrom. At its upper end the slide-rod 27 is provided with a portion 34 that is reduced in diameter and threaded. This portion 34 comprises one of a pair of threaded elements, the other being a nut 35, the portion 34 being re ceived within the threaded bore of the nut 35. The nut 35 is mounted for rotation in the upper end of the standard 2 and confined against axial movement by a screw 36 having a reduced-diameter end 37 that extends into an annular groove 38 in the periphery of the nut. The exposed upper portion of the nut 35 projecting from the standard 2 is formed with an enlarged knurled handgrasp 39 which, if desired, may be provided with suitable indicia to cooperate with other suitable indicia on the adjacent part of the standard to indicate the setting of the work-table It), or to indicate the direction of rotation required to raise or lower the work-table.

The operation of the disclosed mechanism is believed to be obvious from an understanding thereof. Turning of the readily-accessible hand-grasp 39 of the nut 35 will, through cooperation with the threaded bore thereof of the threaded reduced portion 34 of the slide-rod 27, effect vertical sliding movement of the slide-rod 27. By virtue of the crank-arm 33, sliding of the slide-rod 27 will elfect turning of shaft 24 and thus the cam 23. As pointed out above, rotation of the cam 23, through the axial-displacement cam surface 22 which cooperates with the stop-screw 21, will efliect an adjustment of the normal elevated position of the work-table 10.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.

Having thus described the nature of the invention, what 1 claim herein is: t 1

l. A work-table height adjusting means for a blindstitch sewing machine having a frame including a base and a standard rising from one end of said base and carrying a stationary presser-plate, a work-table pivoted to said base at the other end thereof on a horizontal pivot axis arranged generally transverse to said base, resilient means for biasing said Work-table about the pivot-axis thereof toward said presser-plate into an elevated position, and adjustable stop means for limiting the pivotal movement of said work-table under the action of said biasing means, said stop-means comprising a shaft journaled for turning movement longitudinally of said base, an axial displacement cam means mounted upon said shaft and operatively connected to said work-table for effecting pivotal movement of the same toward said presser-plate upon turning of said shaft, a laterally extending crank-arm mounted on said shaft, a slide-rod arranged longitudinally of and mounted for axial sliding in said standard, said slide-rod being operatively connected to said crank-arm to turn said shaft upon sliding of said rod, a threaded element mounted externally of said frame coaxially of said slide-rod, operative connections between said slide-rod and threaded element for effecting axial sliding movement of said slide-rod upon turning of the latter, and means for confining said threaded element against axial sliding.

2. A work-table height adjusting means for a blindstitch sewing machine having a frame including a base and a standard rising from one end of said base and carrying a stationary presser-plate, a work-table pivoted to said base at the other end thereof on a horizontal pivot axis arranged generally transverse to said base, resilient means for biasing said work-table about the pivot-axis thereof toward said resser-plate into an elevated position, and adjustable stop means for limiting the pivotal movement of said work-table under the action of said biasing means, said stopmeans comprising a shaft journaled for turning movement longitudinally of said base, an axial displacement cam means mounted upon said shaft and operatively connected to said work-table for variably. limiting pivotal movement of the same toward said'presser platetupon turning of said shaft, a manually turnableelement mounted on a vertical axis in said standard and extending to the exterior thereof, means for locking said element against axial movement relative to said standard, and operative means between said element and. saidshaft to impart turning to said shaft upon manual actuation of said element.

References Cited in the file of this patent UNITED STATES PATENTS 

